Method for estimating capacity usage status of storage unit, associated memory device and controller thereof

1. A method for estimating a capacity usage status of a storage unit comprising a plurality of sectors, comprising: estimating capacity usage statuses of a portion of sectors; and utilizing a controller to estimate the capacity usage status of the storage unit according to the estimated capacity usage statuses of the portion of sectors in a situation where not all capacity usage statuses of all sectors of the storage unit are estimated.

2. The method of claim 1 , further comprising: reading a variable; and determining the portion of sectors among the plurality of sectors according to the variable.

3. The method of claim 1 , wherein the portion of sectors includes a plurality of discontinuous sectors, and indexes of the discontinuous sectors are an arithmetic series.

4. The method of claim 1 , wherein each of the plurality of sectors includes a plurality of bytes, and the step of estimating the capacity usage statuses of the portion of sectors comprises: for a specific sector of the portion of sectors, determining whether a portion of bytes of the specific sector have data stored therein, and estimating a capacity usage status of the specific sector according to information about whether the portion of bytes of the specific sector have data stored therein in a situation of not determining if all of the bytes of the specific sector have data stored therein.

5. The method of claim 4 , further comprising: reading a variable; and determining the portion of bytes among the plurality of bytes of the specific sector according to the variable.

6. The method of claim 4 , wherein the portion of bytes includes a plurality of discontinuous bytes, and indexes of the discontinuous bytes are an arithmetic series.

7. The method of claim 1 , wherein the portion of sectors comprises at least a first sector and a second sector, and the step of estimating the capacity usage statuses of the portion of sectors comprises: reading data stored in the first sector; transmitting a position command to the storage unit, where the position command is used to ask for data stored in the second sector; after transmitting the position command to the storage device, estimating a capacity usage status of the first sector according to the data read from the first sector; receiving a response message corresponding to the position command from the storage unit; reading data stored in the second sector according to the response message; and estimating a capacity usage status of the second sector according to the data read from the second sector.

8. A controller of a storage device, wherein the controller is utilized for accessing a storage unit comprising a plurality of sectors, the controller comprising: a memory, for storing a program code; and a microprocessor, for executing the program code to estimate a capacity usage status of the storage unit; wherein the microprocessor estimates capacity usage statuses of a portion of sectors; and the microprocessor further estimates the capacity usage status of the storage unit according to the estimated capacity usage statuses of the portion of sectors in a situation where not all capacity usage statuses of all sectors of the storage unit are estimated.

9. The controller of claim 8 , wherein the microprocessor reads a variable and determines the portion of sectors among the plurality of sectors according to the variable.

10. The controller of claim 8 , wherein the portion of sectors includes a plurality of discontinuous sectors, and indexes of the discontinuous sectors are an arithmetic series.

11. The controller of claim 8 , wherein each of the plurality of sectors includes a plurality of bytes, and for a specific sector of the portion of sectors, the microprocessor determines if a portion of bytes of the specific sector have data stored therein, and estimates a capacity usage status of the specific sector according to information about whether the portion of bytes of the specific sector have data stored therein in a situation of not determining if all of the bytes of the specific sector have data stored therein.

12. The controller of claim 11 , wherein the microprocessor reads a variable and determines the portion of bytes among the plurality of bytes of the specific sector according to the variable.

13. The controller of claim 11 , wherein the portion of bytes includes a plurality of discontinuous bytes, and indexes of the discontinuous bytes are an arithmetic series.

14. The controller of claim 8 , wherein the portion of sectors comprises at least a first sector and a second sector, and the microprocessor reads data stored in the first sector; transmits a position command to the storage unit, where the position command is used to ask for data stored in the second sector; after transmitting the position command to the storage device, estimates a capacity usage status of the first sector according to the data read from the first sector; receives a response message corresponding to the position command from the storage unit; reads data stored in the second sector according to the response message; and estimates a capacity usage status of the second sector according to the data read from the second sector.

15. A storage device, comprising: a storage unit comprising a plurality of sectors; and a controller, coupled to the storage unit, for estimating capacity usage statuses of a portion of sectors; and for estimating a capacity usage status of the storage unit according to the estimated capacity usage statuses of the portion of sectors in a situation of not estimating capacity usage statuses of all of the sectors of the storage unit.